This invention relates generally to sheet cleaning, and more particularly, to cleaning a moving flexible sheet which has a leading edge extending transverse to the direction of sheet movement.
When using materials, such as photographic or electrographic film sheets, it is desirable to ensure that the material is free of dust or debris to avoid the formation of defects. Accordingly, sections (e.g., strips or sheets) of the material are moved through a cleaning apparatus to remove any dust or debris adhering to the material. A typical cleaning apparatus includes a rotatable brush having a fibrous surface covering which is brought into brushing contact with the moving material. The fibers have a desired design configuration (i.e., size and stiffness) which, on relative movement between the fibers and the material, causes the fibers to strike adherents and remove them from the material.
While fibrous brushes have generally proven satisfactory in cleaning moving sections of material, some difficulty has been encountered in moving a material section into contact with a fibrous brush. Particularly, if the material section is flexible and the brush is moving counter to the direction of movement of the section in the area where cleaning is to be effected, contact of the brush with the leading edge of the section may damage the section. If a leading edge stiffener is provided to prevent such damage, the action of the brush on such stiffener may prevent the section from moving through the cleaning area. One way of overcoming this described problem is to move the brush away from the travel path of the moving section as the leading edge approaches the brush. However, the time required to return the brush into cleaning contact with the section after passage of its leading edge may result in a significant portion of the section passing by the brush out of cleaning contact whereby such portion is not cleaned.